Tequila (Spanish [teˈkila] (help·info)) is a regional specific name for a distilled beverage made from the blue agave plant, primarily in the area surrounding the city of Tequila, 65 km (40 mi) northwest of Guadalajara, and in the highlands (Los Altos) of the central western Mexican state of Jalisco. Although tequila is similar to mezcal, modern tequila differs somewhat in the method of its production, in the use of only blue agave plants, as well as in its regional specificity.
The red volcanic soil in the surrounding region is particularly well suited to the growing of the blue agave, and more than 300 million of the plants are harvested there each year. Agave tequila grows differently depending on the region. Blue agaves grown in the highlands Los Altos region are larger in size and sweeter in aroma and taste. Agaves harvested in the lowlands, on the other hand, have a more herbaceous fragrance and flavor.
Mexican laws state that tequila can only be produced in the state of Jalisco and limited municipalities in the states of Guanajuato, Michoacán, Nayarit, and Tamaulipas. Tequila is recognized as a Mexican designation of origin product in more than 40 countries. It is protected through NAFTA in Canada and the United States, through bilateral agreements with individual countries such as Japan and Israel, and has been a protected designation of origin product in the constituent countries of the European Union since 1997.
Tequila is most often made at a 38% alcohol content (76 U.S. proof) for domestic consumption, but can be produced between 31 and 55% alcohol content (62 and 110 U.S. proof). Per U.S law, tequila must contain at least 40% alcohol (80 U.S. proof) to be sold in the United States. a
- 1 History
- 2 Production
- 3 Fermentation
- 4 Chemistry
- 5 Aging
- 6 Storage condition
- 7 Types
- 8 Brands
- 9 Serving
- 10 U.S. regulation
- 11 Canadian regulation
- 12 Other uses
- 13 See also
- 14 References
- 15 External links
Tequila was first produced in the 16th century near the location of the city of Tequila, which was not officially established until 1666. The Aztec people had previously made a fermented beverage from the agave plant, long before the Spanish arrived in 1521. When the Spanish conquistadors ran out of their own brandy, they began to distill agave to produce one of North America's first indigenous distilled spirits.
Some 80 years later, around 1600, Don Pedro Sánchez de Tagle, the Marquis of Altamira, began mass-producing tequila at the first factory in the territory of modern-day Jalisco. By 1608, the colonial governor of Nueva Galicia had begun to tax his products. Spain's King Carlos IV granted the Cuervo family the first license to commercially make tequila.
Don Cenobio Sauza, founder of Sauza Tequila and Municipal President of the Village of Tequila from 1884–1885, was the first to export tequila to the United States, and shortened the name from "Tequila Extract" to just "Tequila" for the American markets. Don Cenobio's grandson Don Francisco Javier gained international attention for insisting that "there cannot be tequila where there are no agaves!" His efforts led to the practice that real tequila can come only from the State of Jalisco.
Although some tequilas have remained as family-owned brands, most well-known tequila brands are owned by large multinational corporations. However, over 100 distilleries make over 900 brands of tequila in Mexico and over 2,000 brand names have been registered (2009 statistics). Due to this, each bottle of tequila contains a serial number (NOM) depicting in which distillery the tequila was produced. Because only so many distilleries are used, multiple brands of tequila come from the same location.
In 2003, Mexico issued a proposal that would require all Mexican-made tequila be bottled in Mexico before being exported to other countries. The Mexican government said that bottling tequila in Mexico would guarantee its quality. Liquor companies in the United States said Mexico just wanted to create bottling jobs in their own country, and also claimed this rule would violate international trade agreements and was in discord with usual exporting practices worldwide. The proposal might have resulted in the loss of jobs at plants in California, Arkansas, Missouri, and Kentucky, because Mexican tequila exported in bulk to the United States is bottled in those plants. On January 17, 2006, the United States and Mexico signed an agreement allowing the continued bulk import of tequila into the United States. The agreement also created a "tequila bottlers registry" to identify approved bottlers of tequila and created an agency to monitor the registry.
The Tequila Regulatory Council of Mexico originally did not permit flavored tequila to carry the tequila name. In 2004, the Council decided to allow flavored tequila to be called tequila, with the exception of 100% agave tequila, which still cannot be flavored.
A new Norma Oficial Mexicana (NOM) for tequila (NOM-006-SCFI-2005) was issued in 2006, and among other changes, introduced a category of tequila called extra añejo or "ultra-aged" which must be aged a minimum of three years.
A one-liter bottle of limited-edition premium tequila was sold for $225,000 in July 2006 in Tequila, Jalisco, by the company Tequila Ley .925. The bottle which contained the tequila was a two-kilo display of platinum and gold. The manufacturer received a certificate from The Guinness World Records for the most expensive bottle of tequila spirit ever sold.
In June 2013, the ban on importation of premium (100% blue agave) tequila into China was lifted following a state visit to Mexico by President Xi Jinping. The entry of premium tequila into the country is expected to increase tequila exports by 20 percent within a decade (exports totaled 170 million liters in 2013). Ramon Gonzalez, director of the Consejo Regulador del Tequila, estimates that each of the top 16 producers of tequila had invested up to $3 million to enter the Chinese market. On 30 August 2013, the first 70,380 bottles of premium tequila from ten brands arrived in Shanghai. The arrival happened during an event held at the House of Roosevelt, a well-known club located on The Bund– an area with a long tradition of importing alcoholic beverages in China.
Planting, tending, and harvesting the agave plant remains a manual effort, largely unchanged by modern farm machinery and relying on centuries-old know-how. The men who harvest it, the jimadores [ximaˈðoɾes], have intimate knowledge of how the plants should be cultivated, passed down from generation to generation.
By regularly trimming any quiotes [ˈkjotes] (a several-meter high stalk that grows from the center of the plant), the jimadores prevent the agave from flowering and dying early, allowing it to fully ripen. The jimadores must be able to tell when each plant is ready to be harvested, and using a special knife called a coa (with a circular blade on a long pole), carefully cut away the leaves from the piña (the succulent core of the plant). If harvested too late or too early, the piñas, which can average around 70 kg (150 lb) in the lowlands to 110 kg (240 lb) in the highlands, will not have the right amount of carbohydrates for fermentation.
After harvesting, the piñas [ˈpiɲas] are transported to ovens where they are slowly baked to break down their complex fructans into simple fructoses. Then, the baked piñas are either shredded or mashed under a large stone wheel called a tahona [taˈona]. The pulp fiber, or bagazo [βaˈɣaso], left behind is often reused as compost or animal feed, but can even be burnt as fuel or processed into paper. Some producers like to add a small amount of bagazo back into their fermentation tanks for a stronger agave flavor in the final product.
The extracted agave juice is then poured into either large wooden or stainless steel vats for several days to ferment, resulting in a wort, or mosto [ˈmosto], with low alcohol content. This wort is then distilled once to produce what is called "ordinario [oɾðiˈnaɾio], and then a second time to produce clear "silver" tequila. A few producers[who?] distill the product a third time, but this removes much of the agave flavor from the tequila. From there, the tequila is either bottled as silver tequila, or it is pumped into wooden barrels to age, where it develops a mellower flavor and amber color.
Usually, the differences in taste between tequila made from lowland and highland agave plants is noticeable. Plants grown in the highlands often yield sweeter and fruitier-tasting tequila, while lowland agaves give the tequila an earthier flavor.
Unlike other tequila production steps, fermentation is one of the few steps out of the control of human beings. Fermentation is the conversion of sugars and carbohydrates to alcohol through yeast in aerobic conditions, meaning that oxygen is present during the process. Fermentation is also carried out in a non-aseptic environment which increases the bacterial activity of tequila. The participation of microorganisms from the environment (yeasts and bacteria) makes fermentation a spontaneous process which gives rise to many byproducts that contribute to the flavor and aroma of tequila.
During the fermentation process, inoculum is added to the batch to speed the rate of fermentation. When inoculum is added, fermentation can take approximately 20 hours to 3 days. If inoculum is not added, fermentation could take up to 7 days. The rate of fermentation is a key factor in the quality and flavor of tequila produced. Worts fermented slowly are best because the amount of organoleptic compounds produced are greater. The alcohol content at the end of fermentation lies between 4-9%.
Organoleptic compounds enhance flavor and aroma. These include fusel oil, methanol, aldehydes, organic acids and esters. Production of isoamyl and isobutyl alcohols begins after the sugar level is lowered substantially and continues for several hours after the alcoholic fermentation ends. In contrast, ethanol production begins in the first hours of the fermentation and ends with logarithmic yeast growth. The alcohol content in tequila is affected by three factors. First the amount of isoamyl alcohol and isobutanol is the yeast strain. Second, the carbon:nitrogen ratio. The higher the ratio, the more alcohol produced. And third, the temperature of fermentation. The higher the temperature, the greater concentration of isobutyl and isoamyl alcohols produced. Although if temperatures are too high, this can cause the yeast to become less effective. Similarly, if the temperature is too low, the process occurs too slowly. This can become a large issue in Central Mexico, most precisely the city of Tequila, Jalisco, where most tequila is processed. The average annual temperatures in the city of Tequila can reach 31C. For this reason, tequila producers often use large stainless steel tanks for fermentation.
Organoleptic compounds are dependent on yeast. The role of yeast is to, through many enzymatic processes, turn sugars and carbohydrates into alcohol. There are two steps, first in aerobic conditions, yeast is doubled in colony size every four hours. This process goes on for 24-48 hours. Next, yeast turns acetaldehyde into ethyl alcohol which is known as one of the organoleptic compounds produced in fermentation.
The two main categories of yeast used in tequila are Commercial brewers yeast and yeast that comes from pre cultivated existing yeast that has been preserved. The use of either type of yeast can result in different end products of tequila.
Tequila is a distilled beverage that is made from the fermentation of the sugars found from the blue agave plant once it has been cooked, the main sugar being fructose. Through the fermentation process, many factors influence the higher alcohol content of tequila, which are molecules such as isobutyl alcohol and isoamyl alcohol, and ethanol. These parameters include, the type of yeast strain, the age of the agave plant itself, temperature, and the carbon/nitrogen ratio. However, the type of yeast strain used and the carbon/nitrogen factors have the biggest influence on the production of higher alcohols, this is not surprising as higher alcohol and ethanol production is an intrinsic property of the metabolism of each strain. The type of yeast most commonly found in tequila is Saccharomyces cerevisiae, which contains many strains. For example, CF1 agaves, a type of yeast, produces much more ethanol than a strain of CF2, as the yeast's metabolism mechanisms differ from one another. This factor may be influenced from different agricultural practices that occur to cultivate the different yeasts strains. It was found that the higher the carbon/ nitrogen ratio, the higher the production of higher alcohols such as isobutyl alcohol and isoamyl alcohol. A high ratio imparts that there is less nitrogen in the fermentation process, which results in deamination reactions of amino acids, leading to the synthesis of higher alcohols. The Ehrlich pathway is the name for this process, where a-ceto acids are decarboxylated and transformed to aldehydes and to higher alcohols. The temperature of the fermentation process also greatly effects the alcohol content of the resulting product. For example, a study conducted by Pinal et al. found that cultivating two strains at a temperature of 35 degrees as compared to a temperature of 30 degrees produced more isoamyl alcohol. The higher temperature suggests that this is a much more optimal condition for the yeast to ferment the distilled beverage. Lastly the age of the agave plant itself, the older the plant the greater the alcohol production. It was shown in a study that the concentration of amyl alcohol increased as the plant aged by a factor 30%. However, it is also found that there is a higher concentration of methanol found when using younger plants. This may be due to differences in agricultural practices that occur when taking care of plants of different ages.
Tequila comes in an abundant array of colors that ranges from a simple clear distilled beverage to a dark amber brown. The color of the tequila varies greatly on the aging process and the type of wood used for storage. The white version of tequila, known as silver tequila or blanco, is the product obtained without or very little additional aging process. As well, the spirit must contain between 38-55% alcohol content, which is fermented from a wort, which contains no less than 51% sugars from the agave plant. Consuming silver tequila provides for the purest form as little aging has occurred. What is known as gold, joven or oro tequila is usually silver tequila with the addition of grain alcohols and caramel color, however, some higher end gold tequilas may be a blend of silver and reposado. Rested (reposado) or aged tequila (añejo) are aged in wooden containers. The aging process can last between two months and three years and can create or enhance flavors and aromas. The aging process generally imparts a golden color.
Flavor and aroma
There are more than 300 known compounds in tequila, many of which are produced during the fermentation process, the raw material used, and to a lesser degree, during the maturation. The components that make up tequila do not act individually to give tequila its distinctive flavor and aroma, but rather, depends on the interaction and quantity of each volatile compound. The volatile compounds responsible for the flavor and aroma profiles of the tequila are put into a category called organoleptic compounds and are known to increase in concentration with a slower fermentation process. The organoleptic compounds produced during fermentation include higher order alcohols, methanol, esters, carbonyls, terpenes, and furans.
Higher order alcohols have a strong aroma, and the quantity present in each tequila depends on the carbon:nitrogen ratio and temperature during the cooking and fermentation processes. Some of the most common alcohols present other than ethanol are: isoamyl alcohol, isobutanol, and 1-propanol. Methanol is thought to be mainly generated through hydrolysis of methylated pectin which is naturally present in the agave plant, but there has been speculations that it is also partly produced from the enzymatic reactions of yeast strains containing pectin methyl esterase enzyme which break up the methoxyl group from the pectin. Nearly 50 different esters identified in tequila which together give rise to the fruit like flavors and smell. One of the most abundant esters is ethyl acetate which is synthesized during fermentation by the yeast Saccharomyces cerevisiae, using alcohol transferase enzyme which links acetic acid to ethanol. In general, the longer the controlled fermentation period, the higher yield of esters produced. During the fermentation process, ethanol is oxidized and one of the main compounds produced are acetaldehydes, which adds the flavor necessary for the final product of tequila. The agave plant contains many terpenes such as vanillin and syringaldehydes which presents a strong and fruity or herbal aroma. It also contains eugenol which can deliver a hint of spicy flavor to the tequila. Since the production of tequila involves heating, Maillard browning reactions occur, and furans are produced during the thermal degradation of sugar. The most prominent furanic compounds include 2-furaldehyde and 5-methylfuraldehyde, which can contribute to the smoky flavor of tequila.
Volatile compounds that contribute to the overall taste and aroma of tequila can be quantitatively assessed and evaluated by gas chromatography. Discrimination tests such as duo-trio and triangle tests are also used to evaluate the quality of the tequila.
If silver or white tequila is the desired final product, distillation is the final process it undergoes. Rested (Reposado) or aged (Añejo) tequila must be maturated in 200-liter (or larger) white oak barrels for at least 2 months for the first, and 12 months for the last. There are, however, more than 50 different companies producing tequila in the mexican province of Jalisco, with different maturation times according to the variety of tequila and desired quality of the final product.
All companies producing tequila have their aging processes regulated and fiscalized by the Mexican government.
The maturation process causes four main chemical transformations to the tequila compounds: (1) decreasing of fusel oils by the char in barrels, which acts as an adsorbing agent. (2) extraction of complex wood constituents by tequila, yielding specific aroma and flavor to the final product. (3) reactions among the components of tequila, creating new chemical compounds and (4) oxidation of the original contents of tequila and of those extracted from wood. The final result of these changes are increased concentrations of acids, esters and aldehydes and a decrease in fuel oil concentration.
Reposado may be rested in oak barrels or casks as large as 20,000 liters (5,280 gallons), allowing for richer and more complex flavors. The preferred oak comes from the US, France, or Canada, and is usually white oak. Some companies char the wood to impart a smoky flavor, or use barrels previously used with different kinds of alcohol (e.g. whiskey or wine). Some reposados can also be aged in new wood barrels to achieve the same woody flavor and smoothness, but in less time.
Añejos are often rested in barrels previously used to rest reposados. The barrels cannot be more than 600 liters (158 gallons), and most are in the 200-liter (52-gallon) range. Many of the barrels used are from whiskey distilleries in the US or Canada, and Jack Daniels barrels are especially popular. This treatment creates many of the aspects of the dark color and more complex flavors of the añejo tequila. After aging of at least one year, the añejo can be removed from the wood barrels and placed in stainless steel tanks to reduce the amount of evaporation that can occur in the barrels.
Threats to quality
TMA (tristeza y muerte de agave — "agave depression and death") is a blight that has reduced the production of the agave grown to produce tequila. This has resulted in lower production and higher prices throughout the early 21st century, and due to the long maturation of the plant, will likely continue to affect prices for years to come.
"Tequila worm" misconception
Only certain mezcals, usually from the state of Oaxaca, are ever sold con gusano (with worm). They are added as a marketing gimmick and are not traditional. The tequila regulatory council does not allow gusanos or scorpions (which are sometimes also added to mezcals) to be included in tequila bottles. The worm is actually the larval form of the moth Hypopta agavis, which lives on the agave plant. Finding one in the plant during processing indicates an infestation and, correspondingly, a lower-quality product. However, this misconception continues, despite effort and marketing to represent tequila as a premium liquor—similar to the way Cognac is viewed in relation to other brandies.
Norma Oficial Mexicana
The Norma Oficial Mexicana (NOM) applies to all processes and activities related to the supply of agave, production, bottling, marketing, information, and business practices linked to the distilled alcoholic beverage known as tequila. Tequila must be produced using agave of the species Tequilana Weber Blue variety, grown in the federal states and municipalities indicated in the Declaration.
Furthermore, the NOM establishes the technical specifications and legal requirements for the protection of the Appellation of Origin of "Tequila" in accordance with the current General Declaration of Protection of the Appellation of Origin of "Tequila", the Law, the Industrial Property Law, the Federal Consumer Protection Law and other related legal provisions.
All authentic, regulated tequilas will have a NOM identifier on the bottle. The important laws since 1990 were NOM-006-SCFI-1993, the later update NOM-006-SCFI-1994, and the most recent revision in late 2005, NOM-006-SCFI-2005.
The number after NOM is the distillery number, assigned by the government. NOM does not indicate the location of the distillery, merely the parent company or, in the case where a company leases space in a plant, the physical plant where the tequila was manufactured.
Unlike wine that contains tannins which may change over time, even in a bottle if proper storage conditions are not met, spirituous liquors like tequila do not change much once they are bottled. Since tequila is a distilled liquor, it does not require strict storage conditions like wine does, and the same goes with most other distilled spirits such as whiskey, rum, or vodka. Furthermore, because the characteristics and certain quality (flavor, aroma, color, etc.) of the tequila are determined during the aging process inside wood barrels, the quality of the tequila should remain relatively constant after they are bottled. To maintain the quality of tequila, at least three conditions should be met: constant and moderate temperature (60 to 65 °F), no exposure to direct sunlight, and maintenance of proper seal of the bottle. Also, storage conditions will have more effect on the taste of aged tequila rather than the un-aged tequila. For instance, if stored in improper conditions, the dark and more complex flavors of the añejo tequila are more likely to be tainted than the blanco or the silver tequila.
Once the bottle is opened, the tequila will be subject to oxidation which will continue to happen even if no more oxygen is introduced. In addition, if the bottle has more room for air, the process of oxidation occurs faster on the liquor remaining inside the bottle. Therefore, it may be the best to consume the tequila within one or two years after opening. For the most part, the change in quality of tequila is due to extreme conditions of improper storage, not due to oxidation.
The two basic categories of tequila are mixtos and 100% agave. Mixtos use no less than 51% agave, with other sugars making up the remainder. Mixtos use both glucose and fructose sugars.
Tequila is usually bottled in one of five categories:
- Blanco [ˈblaŋko] ("white") or plata [ˈplata] ("silver"): white spirit, unaged and bottled or stored immediately after distillation, or aged less than two months in stainless steel or neutral oak barrels
- Joven [ˈxoβen] ("young") or oro [ˈoɾo] ("gold"): unaged silver tequila that may be flavored with caramel coloring, oak extract, glycerin, or sugar-based syrup. Could also be the result of blending silver tequila with aged or extra-aged tequila.
- Reposado [repoˈsaðo] ("rested"): aged a minimum of two months, but less than a year in oak barrels of any size
- Añejo [aˈɲexo] ("aged" or "vintage"): aged a minimum of one year, but less than three years in small oak barrels
- Extra Añejo ("extra aged" or "ultra aged"): aged a minimum of three years in oak barrels, this category was established in March 2006.
With 100% agave tequila, blanco or plata is harsher with the bold flavors of the distilled agave up front, while reposado and añejo are smoother, subtler, and more complex. As with other spirits aged in casks, tequila takes on the flavors of the wood, while the harshness of the alcohol mellows. The major flavor distinction with 100% agave tequila is the base ingredient, which is more vegetal than grain spirits (and often more complex).
The Consejo Regulador del Tequila (Tequila Regulatory Council) reported 1377 registered brands from 150 producers for the year 2013.
In Mexico, the most traditional way to drink tequila is neat, without lime and salt. It is popular in some regions to drink fine tequila with a side of sangrita—a sweet, sour, and spicy drink typically made from orange juice, grenadine (or tomato juice), and hot chilli. Equal-sized shots of tequila and sangrita are sipped alternately, without salt or lime. Another popular drink in Mexico is the bandera (flag, in Spanish), named after the Flag of Mexico, it consists of three shot glasses, filled with lime juice (for the green), white tequila, and sangrita (for the red).
Outside Mexico, a single shot of tequila is often served with salt and a slice of lime. This is called tequila cruda and is sometimes referred to as "training wheels", "lick-sip-suck", or "lick-shoot-suck" (referring to the way in which the combination of ingredients is imbibed). The drinkers moisten the back of their hands below the index finger (usually by licking) and pour on the salt. Then the salt is licked off the hand, the tequila is drunk, and the fruit slice is quickly bitten. Groups of drinkers often do this simultaneously. Drinking tequila in this way is often erroneously called a Tequila Slammer, which is in fact a mix of tequila and carbonated drink. Though the traditional Mexican shot is tequila by itself, lime is the fruit of choice when a chaser must be used. The salt is believed to lessen the "burn" of the tequila and the sour fruit balances and enhances the flavor. In Germany and some other countries, tequila oro (gold) is often consumed with cinnamon on a slice of orange after, while tequila blanco (white) is consumed with salt and lime. Finally, as with other popular liquors, a number of shot-related drinking games and "stunt" drinks are used, such as body shots.
If the bottle of tequila does not state on the label that it is manufactured from 100% blue agave (no sugars added), then, by default, that tequila is a mixto (manufactured from at least 60% blue agave). Some tequila distilleries label their tequila as "made with blue agave" or "made from blue agave." However, the Tequila Regulatory Council has stated only tequilas distilled with 100% agave can be designated as "100% agave".
Some distillers of lower-quality tequila have marketed their product to be served "ice-cold chilled" when used as a shot. Chilling any alcohol can be used to reduce the smell or flavors associated with a lower-quality product. Any alcoholic product, when served as a chilled shot, may be more palatable to the consumer.
Many of the higher-quality, 100% agave tequilas do not impart significant alcohol burn, and drinking them with salt and lime is likely to remove much of the flavor. These tequilas are usually sipped from a snifter glass rather than a shot glass, and savoured instead of quickly gulped. Doing so allows the taster to detect subtler fragrances and flavors that would otherwise be missed.
When served neat (without any additional ingredients), tequila is most often served in a narrow shot glass called a caballito (little horse, in Spanish), but can often be found in anything from a snifter to a tumbler.
A variety of cocktails are made with tequila, including the margarita, a cocktail that helped make tequila popular in the United States. The traditional margarita uses tequila, Cointreau, and lime juice, though many variations exist. A popular cocktail in Mexico is the Paloma. Also, a number of martini variants involve tequila, and a large number of tequila drinks are made by adding fruit juice. These include the Tequila Sunrise and the Matador. Sodas and other carbonated drinks are a common mixer, as in the Tequila Slammer.
Under U.S. law (27 CFR 5.22 (g)), Tequila cannot be sold in the U.S. at under 40% alcohol concentration (80 U.S. proof).
According to the Food and Drug Regulations in Canada:
- Tequila is defined as an alcoholic beverage in the category of Liqueurs and Spirituous Cordials.
- Listed in B.02.090, only spirits produced in accordance with the laws of Mexico for production of Tequila for consumption in Mexico can be labelled, packaged, sold or advertised as Tequila in Canada, although diluting the alcoholic strength of the Tequila with water after importation is allowed:
(1) Subject to subsection (2), no person shall label, package, sell or advertise any food as Tequila, or in such a manner that it is likely to be mistaken for Tequila unless it is Tequila manufactured in Mexico as Tequila in accordance with the laws of Mexico applicable in respect of Tequila for consumption in Mexico.
(2) A person may modify Tequila that is imported for the purpose of bottling and sale in Canada as Tequila by the addition of distilled or otherwise purified water to adjust the Tequila to a required strength. SOR/93-603, s. 5.
In 2008, Mexican scientists discovered a method to produce tiny, nanometer-sized synthetic diamonds from 80-proof (40% alcohol) tequila, which they said has the optimal range of water to ethanol for producing synthetic diamonds. This process involves heating the tequila to over 800 °C (1,400 °F) to break its molecular structure and be vaporized into gaseous hydrogen, carbon, and various simple molecules. The carbon molecules are then settled upon steel or silicon trays to form a thin and pure uniform layer. Inexpensive to produce, although far too small for use as jewels, the tiny diamonds were hoped to have numerous commercial and industrial applications such as in computer chips or cutting instruments.
- Ian Chadwick. "In Search of the Blue Agave: Jalisco State". Ianchadwick.com. Retrieved 2010-12-25.
- Jacinto, Rodolfo. "How Is Tequila Made". Tequilaknight.com. Retrieved 2011-03-19.
- "Geography: the Territory of the Appellation of Origin, or TDO". Consejo Regulador del Tequila. 26 June 2000. Retrieved 25 May 2012.
- "100 Percent Agave Tequila Arrives In China". Secretariat of Foreign Affairs. Retrieved 8 January 2015.
- "International Protection of the Tequila Designation of Origin". Consejo Regulador del Tequila. Retrieved 8 January 2015.
- "Official Mexican Standard for Tequila". Cite error: Invalid
<ref>tag; name "tequila.net" defined multiple times with different content (see the help page).
- Chadwick, Ian (2004). "In Search of the Blue Agave: History and Culture".
- Anthony Dias Blue (2004). The Complete Book of Spirits. HarperCollins. p. 112.
- Romo, Miguel Aguilar - El Director General de Normas (2006). "Norma Oficial Mexicana NOM-006-SCFI-2005, BEBIDAS ALCOHÓLICAS-TEQUILA-ESPECIFICACIONES." (PDF).
- Tequila Sparks U.S.-Mexico Flap. Associated Press. CBS News. 2003-09-25.
- Salt, tequila, trade agreement. MSNBC News Services. MSNBC. 2006-01-17.
- Viva Margarita! US, Mexico Ink New Tequila Agreement. CalTrade Report. 2006-01-23.
- Agreement Between the Office of the United States Trade Representative and the Secretaría de Economía of the United Mexican States on Trade in Tequila (pdf). 2006-01-17.
- Arias, Guillermo. Tequila struggles to define itself in Mexico. Associated Press. USA Today. 2004-11-28.
- "Bottle of Tequila Sold for $225,000". Associated Press Online. July 23, 2006.
- "Mexico's tequila industry sees China fueling export boom". Reuters. Retrieved 8 January 2015.
- Ian Chadwick (May 2011). "Cultivation & Agriculture". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "Agave: More than just tequila". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "Harvesting Agave for Tequila". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "Cooking & Milling the Agave Heads". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "Fermentation". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "Tequila Distillation". In Search of the Blue Agave. Retrieved 20 May 2012.
- Ian Chadwick (May 2011). "How Tequila is Aged & Bottled". In Search of the Blue Agave. Retrieved 20 May 2012.
- Judy Hevrdejs (1 May 2011). "Tequila's terroir: Highland and lowland tequilas have distinct flavors". Chicago Tribune. Retrieved 20 May 2012.
- email@example.com, Ian Chadwick,. "In Search of the Blue Agave: Fermenting Tequila". www.ianchadwick.com. Retrieved 2016-03-20.
- "Production of tequila from agave: historical influences and contemporary processes" (PDF).
- Pinal, Leticia; Cedeño, Miguel; Gutiérrez, Humberto; Alvarez-Jacobs, Jaime (1997-01-01). "Fermentation parameters influencing higher alcohol production in the tequila process". Biotechnology Letters. 19 (1): 45–47. doi:10.1023/A:1018362919846. ISSN 0141-5492.
- "Tequila" (PDF).
- Encyclopedia of Food and Health. Academic Press. 2015-08-26. ISBN 9780123849533.
- Arellano, Melchor; Gschaedler, Anne; Alcazar, Montserrat. Major Volatile Compounds Analysis Produced from Mezcal Fermentation Using Gas Chromatography Equipped Headspace (GC–HS). doi:10.5772/33415.
- "Production of tequila from agave: historical influences and contemporary processes". ResearchGate. Retrieved 2016-03-19.
- Rodríguez, David Muñoz; Wrobel, Katarzyna; Wrobel, Kazimierz (2005-08-16). "Determination of aldehydes in tequila by high-performance liquid chromatography with 2,4-dinitrophenylhydrazine derivatization". European Food Research and Technology. 221 (6): 798–802. doi:10.1007/s00217-005-0038-6. ISSN 1438-2377.
- Ian Chadwick (2008-01-14). "In Search of the Blue Agave: Types of Tequila". Ianchadwick.com. Retrieved 2010-12-25.
- Chadwick, Ian (2004). "In Search of the Blue Agave: Industry News & Information".
- Stewart, Amy (2013). The Drunken Botanist. Algonquin Books. p. 16. ISBN 9781616201043. Retrieved 29 May 2015.
- "The Straight Dope: Why is there a worm in bottles of tequila?". www.straightdope.com. Retrieved 2010-01-13.
- Waller, James (2003). Drinkology: The Art and Science of the Cocktail. New York: Stewart, Tabori & Chang. p. 224. ISBN 1-58479-304-X.
Let's get the whole worm thing straight right now, muchachos. If there's a worm at the bottom of your tequila bottle, you've either purchased gag-inducing hooch aimed at gullible gringos, or your top-shelf booze is infested by some kind of alcohol-breathing, alien bug.
- "How Do I Store Liquors Like Whiskey, Tequila, or Rum? Do I Need To Do Anything Special? - CulinaryLore.com". www.culinarylore.com. Retrieved 2016-03-23.
- "TequilaNeat". www.tequilaneat.com. Retrieved 2016-03-23.
- "Marcas de Tequila de Envasado Nacional" (Microsoft Excel) (in Spanish). Consejo Regulador del Tequila A.C. 2013-11-19. Retrieved 2013-12-26.
- "Recipe: Mexican Sangrita & Tequila "Completo"". Retrieved 2008-04-25.
- Spirits and Liqueurs, Andrew Durkan, McGraw-Hill, 1998; ISBN 0-8442-0038-7, ISBN 9780844200385
- "How To Drink Tequila". Retrieved 2008-04-25.
- Tequila Regulatory Council: Classification Retrieved 2011-02-15
- Jacinto, Rodolfo. "Ways Of Drinking Tequila". tequilaknight.com. Retrieved 2011-03-19.
- Chadwick, Ian (2004). "In search of the blue agave Part 7 of 14".
- "Riedel Introduces "THE OFFICIAL TEQUILA GLASS"". Riedel. 2002-04-12.
- "IBA recipe". IBA. Retrieved 3 May 2013.
- Branch, Legislative Services. "Consolidated federal laws of canada, Food and Drug Regulations". laws.justice.gc.ca. Retrieved 2016-03-20.
- Branch, Legislative Services. "Consolidated federal laws of canada, Food and Drug Regulations". laws.justice.gc.ca. Retrieved 2016-03-20.
- Zyga, Lisa (2008-11-07). "Scientists Turn Tequila into Diamonds". physorg.com.
- Morsbach, Greg (2008-11-12). "Diamonds produced from tequila". BBC News.
- Jiwatram, Jaya (2008-11-10). "Creating Diamonds from Tequila". Popular Science. Retrieved 2008-11-15.
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